I am not an expert on every model of early Mauser Sporter, but I love those old rifles.
I have made 2 of them in years past, like the one in the picture, I used GEW-98 actions and followed the old style as closely as I could, from the few I have gotten to handle, and a lot of old pictures.
Getting the barrels in the old 28" length is a bit of a trick, but they can be had by calling around. I found 2 years ago in Montana. The man I got them from said they were old Buhiemiller barrels. I assume he was right, but I don't know for sure.

I made one in a standard 8mm, and another in 338-06.
These are very classy rifles, and they were a lot of fun to make. Too bad I could not keep them.

Steve